Motorboats and other powered watercraft generally include an internal combustion engine cooled by liquid coolant circulated by an engine cooling system. The cooling system derives its cooling effect from cool “raw” water drawn through an intake extending from the hull or other portion of the boat into the body of water in which the motorboat is operating. The raw water is then circulated through the engine directly (referred to as an “open” or “raw water” cooling system), or alternatively through a heat exchanger that in turn cools an isolated engine coolant circulated through the engine (referred to as a “closed” cooling system). Accordingly, in open cooling systems, the engine coolant is in the form of raw water. In contrast, in closed cooling systems, the engine coolant is generally in the form of a liquid chemical (e.g., glycol), fresh water or a mixture thereof, which is isolated from raw water. In both types of cooling systems, the medium, to which the engine heat is ultimately transferred, is generally raw water drawn from the body of water in which the motorboat is operating. Unfortunately, as described below, these bodies of water are increasingly falling victim to an unwanted spread of aquatic invasive species, such as zebra mussels.
The growing presence of aquatic invasive species (“AIS”) in public bodies of water threatens water quality, marine ecology and recreational opportunities. AIS readily attach themselves to submerged objects and often repopulate rampantly to the point of harming local marine ecosystems and interfering with recreational activities, including swimming, fishing and boating. With regards to boating, AIS often infiltrate the raw water intake of a motorboat and attach to inner surfaces of the engine cooling system. Over time, collection of AIS within the cooling system can restrict the ability of raw water to flow through the system, thereby inhibiting the ability of the system to properly cool the engine. Further, unless AIS that infiltrate the systems of a motorboat during operation in a first body of water are killed or otherwise eliminated, they can easily and unknowingly be transferred to a second body of water in which the motorboat subsequently operates, thereby exacerbating the AIS problem in public waterways.
It is well known that AIS can be quickly killed by oxygen deprivation, for example, via exposure to water heated to a temperature of approximately 140 degrees Fahrenheit (° F.) or higher. Accordingly, after operation in a body of water, it is generally desirable to flush the cooling system of a motorboat and other portions of the motorboat exposed to the potentially AIS-infested raw water, with hot water. While some lakes and waterways provide publicly-accessible flushing stations equipped with a hot water supply, others do not. Further, even if a flushing station is provided, it may be positioned at a location that is inconvenient for some boaters, or boaters may be required to wait in long lines to use the station.
While prior attempts have been made to provide systems that treat AIS-affected water passages of a motorboat with water heated by the motorboat engine, such systems have proved deficient in various ways. Accordingly, there remains a need for improvement in systems and methods for heating water to be used for AIS flushing, as well as other onboard applications.